Hydraulic valve

ABSTRACT

In a hydraulic valve ( 10 ), the housing ( 34 ) is composed of plate-shaped segments ( 36  to  46 ). Sections of longitudinal channels ( 96, 97 ) are formed by recesses having cross-section with a closed edge which overlap or are flush with corresponding channel sections of the adjacent channels. Radial channels, which are in communication with a supply connection ( 11, 12 ) or a consumer connection ( 13, 14 ) are formed by radial indentations ( 86  to  89 ) of central openings ( 75, 77, 79  and  81 ) of housing segments ( 38, 40, 42  and  44 ). Grooves ( 91, 92, 93  and  93 ) which widen the cross-section of the central housing channel ( 71 ) within which the valve piston ( 19 ) can slide in a pressure tight manner in the axial direction and/or rotation outwards are formed by recesses ( 75, 77, 79  and  81 ) of the housing segments ( 38, 40, 42  and  44 ) having a larger diameter and which positively overlap the central channel ( 71 ) in cross-section. The segment plate ( 36  to  46 ) are positively and form-fittingly joined and/or materially joined into a dimensionally stable package into which welding material is laid into closed compartments which are formed by recesses ( 121  to  134, 126 ) of the segment plates ( 37  to  45 ) interconnected into groups and which extend over the whole series of joints of the segment plates ( 36  to  46 ).

BACKGROUND OF THE INVENTION

The invention concerns a hydraulic valve, in which by relative movementbetween a piston and a housing, which in spatially defined configurationhas supply and user connections, via which pressure medium can flow froma pressure supply aggregate to a user and from this back to a supplycontainer of the pressure supply aggregate, various defined flow pathscan be selected, which are associated with various defined functions ofthe user, for example, forward movement, resting or backwards movementof the piston of a hydraulic cylinder, wherein in various functionalpositions of the hydraulic valve various respectively definedcombinations of flow paths are opened or closed off or subcombinationsof such paths are opened and other sub-combinations closed off, whereinsegments of such flow paths are formed by grooves in the housing and/orthe piston as well as housing and/or piston channels, whichcommunicatingly connect such path sections with each other or withsupply or as the case may be user connections.

DESCRIPTION OF THE RELATED ART

n-way/m-position-valves of this type are generally known and are offeredas either switch valves which are switchable between discrete functionalpositions or as proportional valves which, with increasing displacementof their piston out of a base position, increasing open up a flow-pathcross-section, and are offered by hydraulic component suppliers in themost compatible, that is, corresponding, variations of knownconfigurations of their supply, user and/or control connections, so thata unit manufactured by one manufacturer is exchangeable with acorresponding unit of another manufacturer.

The housing of such valves is as a rule produced of aluminum or steelcast parts, in which at least the basic shape as defined by a centralthrough-going housing channel, which receives the valve piston, thebasic shape of this channel including widening grooves, the flow in suchgrooves joining lengthwise or transverse channels, which are incommunicating connection with connection openings of the valve housing,as well as the flow or path of channels which internally connect housinggrooves with each other without being directly in communicatingconnection with a supply or user connection of the valve housing, ispredetermined by the shape of a cast core, which is introduced into theouter cast shape, which in turn determines the shape of the outersurfaces of the housing, wherein this cast core after the casting of thevalve housing can fall apart and the core material, fine grained sand,must be quantitatively removed in a simple manner from the cast body.

This embodiment of the valve housing as cast part is completelypractical in the view point of a highest possible fluid-tightness(avoidance of the requirement for an external plugging internally witheach other communicating transverse and longitudinal boreholes of thehousing), the mechanical load carrying capacity and also the somewhatrational manufacturing process; however it is also associated with avariety of serious disadvantages:

Even when it is so organized, that a rational manufacturing process ofnumerous housings is possible in a single casting process, theproduction of the cast core is associated with a high technical demands,which is expensive.

The shapes of the housing hollow spaces in the housing, which duringcasting are filled with sand kernels, must be so constructed or shaped,that the kernel material after the casting is reliably removable aftercasting. Herein it is required, for reasons of the sufficient stabilityof the casting kernels, that minimum cross-sections of cast core batchesare required, which for example connect housing internal grooves of thecentral housing channel with each other.

Since a follow-up processing of the central channel of the cast housing,for example with conventional penetrating tools, is unavoidable in orderto achieve sufficiently precise housing side control edges, throughwhich by positive or negative overlapping with piston side control edgesthe various functional positions of the valve are achievable, the axialseparation of such housing side control edges must as a rule be selectedto be substantially greater than would be necessary from flow technicalreasons. The manufacturing length of the known valves is thus forreasons of product finishing as a rule significantly greater than wouldbe required for physical reasons. Correspondingly, the axial dimensionsof the pistons in linear displacement valves must be greater, which alsoresults in a corresponding enlargement of their mass.

SUMMARY OF THE INVENTION

The task of the invention is thus, to improve a hydraulic valve of theabove-described type such that it can be manufactured, withoutdetracting from the functional characteristics and the precision of thearrangement and construction of its control edges as well as with a goodsealing of the housing, with substantially less expenditure and also canbe produced with significantly smaller spatial dimensions.

According thereto the housing of the valve is assembled fromplanar-parallel, plate-shaped segment-sheets, in which segments oflongitudinal channels of the housing are formed by clearances having across-section with a closed edge, which overlap or are aligned withcorresponding channel sections of adjacent channels; radial channels orsegments of such channels, which are connected in communication with asupply connection or a user connection, are formed by radial bulges ofcentral openings of the housing segments, which are oriented or providedalong a common central longitudinal axis; the cross-section of a housingchannel defined by the edges of a central opening, within which thevalve piston in pressure type manner is axially displaceable and/orrotationally turnable, radial widening grooves are formed by clearancesof larger diameter of the housing segment which positively overlap thecentral channel in cross-section; the segment plates are materiallyjoined by brazing, wherein during the brazing process they arepositively and form-fittingly joined or in certain cases materiallyjoined into a dimensionally stable package; a brazing material requiredfor the mechanically secure material joining of the segment plates isintroduced into enclosed compartments, which are formed by group-wiseinterconnecting clearances of the segment plates and which extend overthe entire series of the segment plates.

By this design of the inventive valve technical advantages are achievedincluding at least the following: The clearances or through-holes of theindividual segment sheets can be produced on NC- or CNC-controlled boreand/or punching or stamping machines with high precision, wherein alsochannel paths can be produced in simple manner, which in castingtechnology practically are not realizable or are realizable only atgreat expense.

Since axial groove widths are determined in simple manner by thethickness of the segment sheets, which by the edge of their clearancesdetermines the flow path of the groove base, such groove widths can insimple manner be limited to the physically required minimal value andfor example in the case of magnet controlled linear displacement valves,can be tailored to the lift or stroke of the available control magnets,whereby shortenings of the axial construction length of the valvehousing can be achieved which correspond to 30% of the constructionlength of a conventional valve housing. The mass of the piston is alsoreduced by a corresponding percentage value.

The thin brazed layers, which are produced as a result of the capillaryaction between the sheet metal plate segments, produce an absolute tightand secured connection of the housing segments with each other. Thesealing and mechanical load capacity of the housing is equivalent tothat of a conventional cast housing. It can further be said that thecasting flaws which are statistically unavoidable with cast housings,for example contraction cavities, cannot occur, so t hat the valvehousings produced according to the invention are produced with astatically lower reject quota. As a result of providing the brazingmaterial in closed compartments, there is also made possible a veryprecise measurement of the brazing amount for the respective segmentplate surfaces to be brazed to each other.

It can also be advantageous when the receiving space for the wire shapedbrazing material is designed as a confluent channel, which, runningmeanderingly or spiral shaped, extends through the housing and in thefinished valve is usable as a flow-through *channel for cooling mediumor gas. Such a channel can be produced during the construction processintended for producing the housing without difficulty, such that thecooling fluid flows through the thermally particularly stressed z onesof the valve housing and that in accordance therewith a effectiveremoval of heat is possible.

By the possibility of producing enclosed hollow spaces, which in castingtechnology is not possible, it is also possible to realize a lightconstruction manner with substantial weight savings, without having tosacrifice stability. Further there exits the possibility, to connectrelatively large volume spaces with small channels, in order for exampleto achieve the effect of a buffer.

A follow-up processing of the housing is essentially necessary only inthe manner, that the respective circular spaced, central openings of thehousing segment, in which the valve piston is mounted pressure-tightrotatably or axially slidable, are to be brought into exactcorresponding diameter and exact aligned arrangement with each other.Given as preconditions the manufacturing precision which is conventionalfor NC- and CNC-controlled processing machines for the individual platesegments of the housing as well as their positionally correctform-fixing prior to the brazing process, which is achievable withoutmore by simple alignment aids, the follow up processing of the housingcan as a rule be limited to the honing processing of the centralclearance of the segment plates, which is not associated with a seamforming of the control edges, which from the manufacturing technicalprospective is likewise of substantial advantage. The inventive valve isthus overall substantially more economical to produce than the valvewith a housing formed by casting technology.

For the arrangement of reception channels for brazing material, whichextend over the entire length between the end plates of the segmentpackage, or only over segments thereof, however are in positive overlapwith each other, at least in all cases are interrupted by only onesegment from each other, it is in each case advantageous, when suchreceiver channels are arranged axially symmetric with respect to thecentral longitudinal axis of the central housing channel, that is, inareas, which correspond respectively approximately to the radialseparation from the at the furthest removed surface areas which must bejoined by brazing.

For positionally correct prefixing of the segment plates to each otheras required prior to the brazing process, fixing posts can be used whichextend between the end segments of the segment packages and transitionthrough clearances of the plate shaped segments aligned with each otherand in a form of post-like pull anchors secured to one or the other ofthe end segments, which is riveted on the other side of the package withthe there situated end plate, but also “loose” fixing posts, which areriveted respectively with both end plates of the segment package. Ineach case it is advantageous when the diameter of the fixing postscorrespond to the diameter of the alignment clearances of the housingsegments, so that the fixing posts are also useable for the mutual orinter-changeable centering adjustment of the segment plates.

The positionally correct prefixing of the segment plates for the brazingprocess is also possible in the manner, that the segment plate packageis form fittingly held together by caulking anchoring bodies laid intoedge opening recesses of the edges of the plate shaped segments alignedwith each other, wherein the edge openings, with each other alignedrecesses preferably form a longitudinal groove with a towards outwardsnarrowing trapezoid cross-sectional shaped interstitial space, and theanchoring bodies are formed as flat or shallow arched posts or slats,which by pressing into the groove achieve the form locking anchoring ofthe plate shaped segments.

A suitable form-stable fixing of the segment package of the housing canalso be thereby achieved, when the segment plates are materially joinedor bonded with each other by small welding beads, which in suitable,preferably axially symmetric arrangement are applied over the platejoints. It is a precondition for this, that the segment plates duringthe welding or brazing can be held to each other in their characteristicconfiguration necessary for the finished housing.

A positionally correct fixing of the plate shape segments to each other,which is at the same time automatic, is also thereby achievable, in thatsegment plates arranged adjacent each other are provided with co-axialprojections and clearances of approximately complimentary shape and thesegment plates are form fixably joined to each other by pressing in ofthe projections into the clearances of the adjacent segment plate(s).

This type of positionally correct fixing of the segment plates to eachother is, when these are constructed to be relatively thick, possiblefrom the manufacturing technology in a simple manner thereby, that theprojections are formed by the material from the stamped-out cavities,wherein the stamp stroke penetrates only through a portion, preferablythe major portion, of the material thickness of the respective segmentplate.

When the thickness of such plate shaped segments of the housing, inwhich the edge of their central clearances respectively define thegroove basis of a groove extending through the central channel of thehousing, the axial separation of the groove side wall forming segmentplates or one of the natural break of these separation correspondingand/or the thickness of the plate segments, the groove side wall of twoby a ring flange with respect to each other bordered housing ringgrooves form, the thickness of the respective ring flanges or a naturalbreak of the same correspondence, so can in principle all plate shapesegments of the valve housing have the same thickness or be assembled ofsegment elements of the same thickness.

Consequently following of the inventive concept the valve piston canalso be comprised of solidly with each other welded circular disk shapedsegment plates, according to the base shape, so that also the axialwidth and radial depth of grooves of the piston and the thickness ofsuch grooves with respect to each other separated piston flanges can bedetermined by the thickness of the segment plates or as the case may bea multiple of a minimum thickness.

The same is valid in concept for an intermediate sleeve introduced inthe central channel of the housing, which coaxially encompasses thepiston and for its part is comprised of ring disk shaped, solidly weldedto each other segments of the same internal diameter d_(i).

Such an intermediate sleeve can in alternative embodiments of the valvebe fixedly connected with the housing thereof or fixedly connected withthe relative to the housing moveable valve piston and makes possible inboth cases in simple manner the realization of ring channels of thehousing, for example the piston, which channels form the flow paths ofthe valves. The intermediate sleeve can however also be formed of amoveable valve element moveable relative to the housing and a central,rigidly with this connected piston, via the displacement or rotationalturning of which the various functional positions of the valve areselectable.

In a preferred embodiment of the inventive valve both the piston thereofas well also the intermediate sleeve thereof are formed moveable withrespect to each other and relative to the housing.

In this embodiment the valve can be formed as servo-regulator valve, inwhich either the piston is employed as the desired position inputelement and the intermediate sleeve as the actual value feedback elementor the housing as desired value input element and the piston as actualfeedback element.

The until now described form of the valve housing, the piston and apiston coaxially encompassing intermediate sleeve is particularlysuitable for an embodiment of the valve as turn slide valve, with easymovement of the valve elements relatively to each other, withoutdetracting from the good sealing of the separation of flow paths setunder high pressure against those which are in lower pressure levels,for example the ambient pressure.

BRIEF DESCRIPTION OF THE DRAWINGS

Further details of the inventive hydraulic valve can be seen from thefollowing description of illustrative embodiments of the same byreference to the drawings. There are shown:

FIG. 1 an inventive hydraulic valve with a housing formed of assembledplate shaped segments in schematic simplified prospectiverepresentation, partially in section along a vertical longitudinalmiddle plane of the housing along its central longitudinal axis as wellas the longitudinal axis of pressure (P) and tank (T)-connectionchannels of the valve, partially as a view of its connection side outersurface,

FIG. 1a the valve according to FIG. 1 in section along its verticallongitudinal middle plane,

FIG. 1b the valve according to FIG. 1 in section along its transversemiddle plane which contains the central longitudinal axis and extends ata right angle to the vertical longitudinal middle plane,

FIG. 1c the housing of the valve according to FIG. 1, in a sectionalrepresentation corresponding to FIG. 1,

FIG. 1d a view of the housing segment adjacent the connection side endsegment of the housing,

FIG. 2 a simplified hydraulic switch diagram for explanation of thefunction of the valve according to FIG. 1,

FIG. 3 the plate shaped segments of the valve housing as well aslikewise also plate shaped segment designed elements of the valve pistonand one of the piston within the central valve housing channel coaxialsurrounding intermediate sleeve in exploded, simplified perspectiverepresentation, the piston and intermediate sleeve segments in enlargedscale in comparison to the representation of the housing segment,

FIG. 3a a part of the piston and jacket segment according to FIG. 3 incomparatively enlarged scale,

FIG. 4 a further embodiment of a valve which is a constructional andfunctional analog of the hydraulic valve according to FIG. 1, and

FIG. 5 a servo-hydraulic valve in a supplied embodiment which is aconstructional analog to the valve according to FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION

The hydraulic valve referenced overall in FIGS. 1 through 3 with is forpurposes of explanation, without reduction of the scope of theinvention, formed as a rotary slide valve, which has the function of a4/3-way proportional valve. It has a blocking base position 0 in which apressure (P) supply source connection 11 as well as a return flow (T)connection 12 are blocked against a user (A)-connection 13 as well asagainst a further user (B)-connection 14, which are connected with thedrive pressure spaces 16 and 17 of user represented in FIG. 2 as doubleacting linear hydraulic cylinder 18.

By turning of the generally with 19 indicated piston of the valve 10 inthe clockwise direction represented by arrow 21 in FIG. 1 and 3 about anazimuthal amount ₁ the valve 10 can be placed in a function position Iin which via a flow path 22 over the valve 10 the one drive pressurespace 16 of the hydraulic cylinder 18 is connected which the P-supplyconnection 11 of the valve 10 and the other drive pressure space 17 ofthe hydraulic cylinder 18 via a flow path 22 of the valve 10 isconnected with the T-connection 12 of the valve 10, so that the piston24 of the hydraulic cylinder 18 is moved in the direction of the arrow26 of FIG. 2, according to the representation towards the right.

By turning of the valve piston 19 in the by the arrow 27 in FIG. 1represented azimuthal direction₂, in counter-clockwise direction, sothen the valve 10 comes into its functional position II which isalternative to the functional position I, in which the other drivepressure space 17 of the user 18 via a flow path 28 of the valve 10 isconnected with the P-supply connection 11, on which the high outputpressure P of the pressure supply aggregate 29 is available, while thein the functional position I of the valve 10 with the P-supplyconnection 11 of the valve 10 connected drive pressure space 16 of theuser 18 now via a flow path 31 with the no-pressure tank 32 of thepressure supply aggregate 29 is connected, so that in the functionalposition II the valve 10 of the piston 24 of the user 18 moves to theleft in the direction of the arrow 35 of FIG. 2, according to therepresentation.

For the valve 10 the characteristic is a presumed, that the hydraulicfluid flow, which in the functional positions I and II via the valve tothe user 18 and from this can flow back into the tank 32 of the pressuresupply aggregate 29, are increasingly greater, the further the piston 19is azimuthally deflected from its functional neutral base position 0 inwhich the user 18 is brought to rest.

Rotary slide valves, which fulfill the above described functions, aswell as also functional analog linear slide valves, are generally knownalso in embodiments, in which for example in the base position of thevalve the P- and T-connections thereof are connected with each other, sothat the pump 33 of the pressure supply aggregate 27 can be operated ina circulating operation.

In distinction to conventional valves of the known type the housinggenerally referenced with 34 is formed by assembly of plate shaped,steel sheet comprising segments 36 through 46, of which the largesurface areas are connected with each other by brazing.

In a manner analogous to the segmented construction of the housing 34the piston 19 of the valve 10 is formed by welding together circulardisk shaped segments 48 through 56 according to the basic design.

A corresponding segmental construction is also possible for tubularshaped cylinder intermediate sleeve indicated with an overall 58, whichaccording to the desired base shape is comprised of ring shaped, solidlywith each other welded segments 61 through 69.

The housing 34 of the valve 10 has a central, through-going housingchannel 71 (FIG. 1c) of segments of the length, which correspond to thethickness of the plate shaped housing segments 36 through 46, which isformed by the edges sequentially following along the centrallongitudinal axis 72 of the central channel 71 and into each othertransitioning central openings 73 through 83 of the plate shaped housingsegments 36 through 46.

The closed edged circular shaped openings 73, 74, 76, 78, 80, 82 and 83of the plate shaped housing segments 36, 37, 39, 41, 43, 45 and 46 andthe opening 75, 77, 79 and 81 of the remaining plate shaped housingsegments 38, 40, 42 and 44 which have circular arch shaped edges overthe main portion of the azimuthal area edged and of which the centralopenings are provided with slit shaped radial voids 86, 87 and 88 or asthe case may be 89, are provided coaxially with respect to the centrallongitudinal axis 72 of the central housing channel 71.

Via ring groove segments 38, 40, 42 and 44, which are pairwise providedbetween ring flange-segments 37, 39, 41, 43 and 45 of the plate shapedhousing segments 36 through 46, whereby the diameter d_(F) (FIG. 1a) ofthe central opening 74, 76, 78, 80 and 82 of the ring flange segment 37,39, 41, 43 and 45 of the plate shaped housing segments is somewhatsmaller than that (d_(N)) of the opening of the between respectively toring flange segments provided ring groove segments 38, 40, 42 and 44 ofthe housing 34, there are formed within the housing 34 central channelsegmentwise radially widening ring grooves 91 through 94, namely aT-(supply)-connection groove 91, an A-(user)-connection groove 92, aB-(user)-connection groove 93 and a P-(pressure supply)-connectiongroove 94, wherein the A-connection groove and the B-connection grove 93are provided between the T-connection groove 91 and the P-connectiongroove 94 and hereby the A-connection groove 92 is provided betweenT-connection groove 91 and the B-connection groove 93, which is providedadjacent the P-connection groove 94.

The connection end of the housing 34 is formed by the connection segment36, on which, in a bore shape customary for a 4/3 way valve standardconnection bore holes for the P-supply connection 11, the T-connection12, the A-user connection 13 and the B-supply connection 14 areprovided.

The ring flange segment 37 adjacent that of the connection segment 36 ofthe housing 34 is provided with a circular clearance 12 ₁ aligned withthe T-connection bore hole 12 of the connection segment 36, whichtogether with the connection bore hole 12 forms an in the radial bulge86 of the central opening 77 of the T-groove segment 38 connectingT-longitudinal channel 96 (FIG. 1a), which via the radial bulge 86formed transverse channel is in continuous communicating connection withthe T-connection groove 91 of the housing 34.

The associated housing segments 37 through 43 between the connectionsegment 36 and the P-ring groove segment 44 are provided with circularclearances 11 ₁ through 11 ₇ which are in alignment with theP-connection bore holes 11 of the connection segment 36 so that acontinuous communicating connection exists between the P-supplyconnection 11 and the P-ring groove 94 of the housing 34. The centrallongitudinal axis 72 of the central channel 71 of the housing 34 as wellas the central longitudinal axis 98 of the T-longitudinal channel 96 andthe central longitudinal axis 99 of the P-channel 97 lie in a commonplane 101, which according to the representation of FIGS. 1 and 1d isshown as a “vertical” longitudinal middle plane of the housing 34.

The housing segments 37, 38 and 39 provided between the connectionsegment 36 and the A-ring groove segment 40 are provided with roundclearances 13 ₁ and 13 ₂ or, as the case may be, 13 ₃ which are inalignment with the A-user connection bore hole 13 of the connectionsegment 36, which overall form an A-longitudinal channel 102 (FIG. 1b),which connects in the radial projection 87 of the central opening 77 ofthe A-ring groove segment 40, whereby again continuous communicatingconnection of the A-user connection 13 is established with theA-connection groove 92 of the housing 34.

The housing segment 37 through 41 positioned between the connectionsegment 36 of the housing 34 and its B-ring groove segment 42 areprovided with round clearances 14 ₁, a 14 ₂ 14 ₃, 14 ₄ and 14 ₅ whichare in alignment with the B-connection bore holes 14 of the connectionsegment 36, which form a B-longitudinal channel 103, which connects inthe channel formed by the radial projection 88 of the central opening 79of the B-ring groove segment 42, which is in communicating connectionwith the B-ring groove 93 of the housing 34, so that also theircontinuous communication connection is provided with the B-use-connection 14 of the valve 10.

The central longitudinal axis 104 of the A-longitudinal channel 102 andthe central longitudinal axis 106 of the B-longitudinal channel 103 liein the right-angular to the longitudinal plane 101 of the housing 34running transverse middle plane 107 which transects the verticallongitudinal plane 101 along the central longitudinal axis 72 of thehousing 34.

The cumulative housing segments 36 through 46 are respectively providedwith four circular round alignment clearances 108, which are arranged inthe same, four-fold axial symmetric grouping with respect to the commoncentral longitudinal axis 72 of the central opening 73 through 83 of thehousing segments 36 through 46 and in the same radial separation fromthe central longitudinal axis 72 as the P-connection bore hole 11 andthe A- and B-connection bore holes 13 and 14 and are pair-wise arrangedin planes, which lie at 45° to the central planes 101 and 107 of thehousing 34.

In the respective orientation of the plate shaped housing segments 36through 46, in which their T-channel clearances 12 and 121 ₁ theirP-channel clearances 11 and 11 ₁ through 11 ₇ as well as their A-channelclearances 13 and 131 through 133 and their B-channel clearances 14 and14 ₁ through 14 ₅ respectively with each other align, there are alsorespectively eleven of the alignment bore holes 108 positioned inalignment along the central longitudinal axis 111 through 114, so thatthis configuration of the plate shaped housing segments 36 through 46can be form fittingly joined by insertion of cylindrical-rod shapedfixing rods 116 through 119 of which the diameter, except for anegligible tolerance, corresponds to that of the alignment clearances108. By riveting the ends of the fixing rods 116 through 119 with theconnection segment 36 and the operation side closure segment 46 of thehousing 34 these plate shaped segments 36 through 46 are cumulativelyform-fittingly joined in the appropriate configuration for weldingtogether.

The azimuthal angular separation of the vertical axis 111 through 114 ofthe respective with each other aligned clearances 108 from the verticallongitudinal middle plane 101 of the housing 34 corresponds, in therepresented embodiment selected for purposes of explanation, torespectively 30° .

The plate shaped housing segments 37 through 45 positioned betweenconnection segment 36 and closure segment 46, are further provided withthrough-going, circular-cylindrical clearances 121 of the same diameter,of which the central axis lies upon the same “bore” circle as thecentral longitudinal axis 111 through 114 of the alignment clearances108 and from the vertical longitudinal middle plane 101 of the housing34 are oriented in an angular separation of respectively 60°. Theseclearances 121 form the radial edges of the receiver channels for, forexample, wire shaped brazing material, which extend along the length ofthe segment-package formed by the housing segments 37 through 45 andwhich are closed off to the outside by the connection segment 36 as wellas by the closure segment 46 of the housing 34.

Further brazing material receiving channels, which form self enclosedbore spaces of the housing 34, are formed by pairwise with each otheraligned axially, circular cylindrical clearances 122 of the housingsegment 37 and 38, which between the connection segment 36 and the thisoppositely lying ring flange segment 39 are positioned or oriented,which form the one side axial bordering or limitation of theA-connection groove 92.

Further self-enclosed receiving channels or chambers for brazingmaterial are formed by circular cylindrical clearances 123 and of thesame diameter, aligned with each other, in housing segments 40 through45 between the ring flange segment 39 and the connection segment 46,wherein these clearances 123 are provided diametrically opposite to theP-longitudinal channel 97 of the housing 34.

A further brazing material receiving compartment, which is selfenclosed, is bordered by aligned, circular-cylindrical clearances 124 ofthe respective housing segments 42 through 45, which are providedbetween the central ring flange segment 41 of the housing 34 and itsclosure segment 46.

A further, self enclosed receiving space for brazing material is finallybordered by with each aligned, circular cylindrical clearances 126 ofthe ring groove segment 44 and the ring flange segment 45, which arepositioned between the closure segment 46 and the this adjacent ringflange segment 43 of the housing 34 and by these are closed off in theaxial direction.

The central longitudinal axis of the respective brazing receivercompartments, which extend between the central ring flange segment 41and the connection segment 46 of the housing 34, align with the centrallongitudinal axis 104 of the A-longitudinal channel 102 of the housing34, while the central longitudinal axis of the shorter brazing materialreception space, which extends between the closure segment 46 and thering flange segment 43, which borders the P-groove 84 against the B-ringgroove 93 of the housing 34, aligns with the central longitudinal axis106 of the B-longitudinal channel 103 of the housing 34.

The connection segment 36, the to this adjacent ring flange segment 37,the upon this following T-ring groove segment 38 and the upon thisfollowing ring flange segment 39 of the housing 34 respectively have thesame, essentially linear bordered outer contour. They have, as best seenin the detailed representation of FIG. 1d, a quadrilateral base area127, which, right angularly to the central longitudinal center plane 101of the housing 34 measured or determined, has the breadth B, a to thisbase area connecting, same sided-trapezoid shaped intermediate area 128,of which the side edges 29 enclose with the central longitudinal centerplane 101 an angle of 45°, and a to the trapezoid shaped intermediatearea 128 connecting, the base shape according to a right-angledhead-area 131, of which the breadth measured right angularly to thevertical longitudinal center plane 101 of the housing 34 corresponds, inthe embodiment selected for explanation, to ⅔ of the breadth B of thebase area 127 and of which the parallel to the vertical longitudinalcenter plane 101 of the housing 34 measured height corresponds to ⅓ ofthe breadth B of the base area 127.

The connection segment 46 corresponds with respect to the extension ofits outer contour and its measurement or dimension to the quadricbase-area 127 of the connection segment 36 or, as the case may be, theadjacent ring flange segment 37 represented in FIG. 1d.

The housing segments 40 through 45, which are provided between theclosure segment 46 and the next adjacent ring flange segment 39, ofwhich the outer contour corresponds to that of the connection segment36, have identical outer contours 132, drawn in FIG. 1d in dashed lines,which correspond to that of a cross, which both with respect to thevertical longitudinal center plane 101 of the housing 34 as well alsowith respect to the horizontal transverse center plane 107 thereof itssymmetrically formed, wherein the linear running vertical and horizontalend face edges 133 and 134 of the cross shaped housing segment 40through 45 align with vertical and horizontal limitation edges 136 or asthe case may be 137 (FIG. 3) of the closure segment 46 and have the samelength, which corresponds respectively to the half breadth B of the baseof the closure element 46 and the connection element 36.

Between the vertical and horizontal limitation edges 133 and 134 of thecross shaped housing elements are respectively circular bowed shapedconcave bent transition areas 138, of which the curvature center orfocal points lie in the corners of the quadric base area 127.

The closing off segment 46 is provided with circular cylindricalthrough-openings 139 in proximity to its corners for not shown anchorscrews, by means of which the valve 10 is screwable onto a likewise notshown connection block. These anchor screws pass along the concave benttransition edges 138 of the cross shaped housing segment 40 through 45and pass through elongated hole shaped insertion openings 141, which inone of their arrangements of the circular round insertion openings 139of the closing off segment 46 corresponding arrangements in immediateproximity to the corners of the quadrilateral base area 127 of theconnection segment 36 and which is provided with this contour identicalhousing segment 37, 38 and 39, wherein the longitudinal plane 142 of theelongate hole-shaped insertion opening respectively runs at 45° to thelongitudinal middle plane 101 and to the transverse middle plane 107 ofthe housing 34 and contain the central longitudinal axis 143 of thecircular shaped insertion openings 139 of the closing off segment 46.The diameter d_(A) (FIG. 1a) of the central opening 73 of the connectionsegment 36 is somewhat larger than the diameter d_(F) of the centralopening 74 of the adjacent housing segment 37. Via the central opening73 of the connection segment 36 waste oil exiting from the valve 10 canflow off to a waste oil channel of the not shown connection block. Alsothe diameter d_(A) of the circular round central opening 83 of theclosing off segment 46 is larger than the diameter d_(F) of the adjacentcross-shaped housing segment 45 and, in the illustrated special workingembodiment, also slightly larger than the diameter d_(A) of the centralopening 73 of the connection segment 36. A piston 19 engaging operatingelement 144 can extend through the central opening 83 of the connectionsegment 46, as schematically shown in FIG. 2, by means of which thepiston 19, for example, by motor control, is rotatable in thealternative rotation directions 21 or 27 about the central longitudinalaxis 72 of the valve 10.

For a further explanation of the valve 10 an embodiment is envisionedwherein the intermediate sleeve 58 is introduced fixed in the centralchannel 71 of the housing 34 and the piston 19 is provided essentiallyrotatable, however axially non-displaceable.

The intermediate sleeve 58 is in this embodiment selected forillustrative purposes comprised of the ring disk shaped segments 61through 69, which, in substantial analogy to the construction orassembly of the housing 34 of the valve 10, are welded rigidly with eachother in coaxial arrangement with respect to their central longitudinalaxis 72. The ring disk shaped segments 61 through 69 of the intermediatehousing 58 have all the same inner diameter d_(i) so that by thecumulativeness of the sleeve segments 61 through 69 a through-going,central, overall bore hole shaped channel 146 with circular-cylinderinner jacket surface is formed, in which the piston 19 is provided,which during the for explanation selected embodiment is produced in asegment construction manner analogous to that for the realization of theintermediate sleeve 58, with its flange-segments 48, 50, 52, 54 and 56pressure tight slideably and rotatably.

The intermediate sleeve 58 encompasses the self-enclosed ringflange-elements 61, 63, 65, 67 and 69 of the outer diameter d_(F) , aswell as the between respective two of the ring flange element providedring groove-segments 62, 64, 66 and 68 of the small outer diameter d_(R)(FIG. 1a). By these ring shaped housing segments 61 through 69 there areformed radially outer ring grooves 91′, 91′, 93′ and 94′ of theintermediate sleeve 58, which together with the inner ring grooves 91through 94 of the housing 34 produce essentially closed ring channels91″ through 94″, namely the T-ring channel 91″, which is incommunicating connection with the T-return flow connection 12 of thevalve, the A-ring channel 92″, which is in communicating connection withthe A-user connection 13 of the valve, the B-ring channel 93″, whichcommunicates with the B-user connection 14 of the valve 10, as well asthe P-ring channel 94″, which is in communication connection with thepressure (P)-supply connection 11 of the valve 10.

The axial thickness of the ring flange elements 61, 63, 65, 67 and 69 ofthe intermediate sleeve 58 correspond to the thicknesses of the ringflange segments 37, 39, 41, 43 and 45, of which the central openings 74,76, 78 and 80 or, as the case may be, 82, the ring flange segments ofthe intermediate sleeve 58 are provided arranged in alignment of theirring face surfaces with the large surface bordering sides of the housingsegments.

In the same sense the same thickness relation applies for the ringgroove segments 62, 64, 66 and 68 of the intermediate sleeve 58 withrespect to the thicknesses of the ring notch segments 38, 40, 42, and 44of the housing 34 through which it axially extends.

The mentioned thickness relationship applies also for the flange segment48, 50, 52, 54 and 56 as well also to the groove-segments 49, 51, 53 and55 of the piston 19 provided between each two of these flange segmentswith respect to these segments 48 through 56 coaxially encompassing ringshaped shell segments 61 through 69 of the intermediate sleeve 58, inwhich the piston 19 is so provided that the outer end surfaces of itsend flange segments 48 and 56 align with the outer ring face surface ofthe free ring flange segments 61 and 69 of the intermediate sleeve 58.

For further explanation of details of the intermediate sleeve 58 and thepiston 19 reference is now made to the enlarged segment representationof FIG. 3a.

The ring notch segment 64 and 66 positioned respectively adjacent thecentral ring flange segment 65 of the intermediate sleeve 58, which formthe radial inner border of the A-ring channel 92″ or, as the case maybe, the B-ring channel 93″, are provided with respectively two axial andradial through-going control slits 147 and 148 or, as the case may be,149 and 151 which after the welding together of the ring shaped sleevesegments 61 through 69 are formed by erosion. The control slits 147 and148 of the ring groove segment 64, which radially internally border theA-ring space 92″, and the control slits 149 and 151 which form theradial inner borders of the B-ring space 93″ ring space segment 66 ofthe intermediate sleeve 58 are with respect to their centrallongitudinal axis 72 of the valve 10 respectively provided diametricallyopposite to each other. The longitudinal bordering surfaces 152 and 153of the inner control slit 147 and the longitudinal bordering surfaces154 and 156 of the other control slit 148 of the A-groove segment 64 ofthe intermediate sleeve 58 run parallel to each other as well asparallel to the central longitudinal axis 72 of the valve 10, whereinrespectively two longitudinal bordering surfaces 152 and 156 or as thecase may be 153 and 154 align with each other.

Accordingly, also in the B-ring groove segment 66 of the intermediatesleeve 58 the longitudinal bordering surfaces 157 and 158 as well as 159and 161 of its control slits 149 and 151 run parallel to each other andpair-wise in alignment.

The common longitudinal central plane 162 of the control slits 147 and148 of the A-groove segment 64 which contain the central longitudinalaxis 72 of the rotation slide valve, runs at a right angle to that ofthe central longitudinal axis 72 containing common longitudinal centralplane 163 of the two control slits 149 and 151 of the B-groove segment166 of the intermediate sleeve 58.

The between the radial inner longitudinal edges 164 ₁ and 164 ₂ of thecontrol slit 147 and the radial inner longitudinal edges 164 ₃ as wellas 164 ₄ of the control slit 148 of the A-groove segment 64 as well asthe between the radial inner longitudinal edges 166 ₁ and 166 ₂ of thecontrol slit 149 and the between the radial inner longitudinal edge 166₃ and 166 ₄ of the control slit 151 of the B-groove segment 66 of theintermediate sleeve 58, azimuthal width of the control slit 147 and 148or as the case may be 149 and 151 correspond in the illustrativeembodiment respectively to 90°.

The A-groove segment 64 and the B-groove segment 66 of the intermediatesleeve 58 are in the illustrative embodiment are oriented so “turned”with respect to each other, that the longitudinal central plane 162 and163 of the control slits 147 and 148 of the A-groove segment 164 or asthe case may be the control slit 149 and 151 of the B-groove segment 66respectively enclose an angle of 45° with the vertical longitudinalplane 101 of the housing 34.

Also the piston 19 of the valve 10 which in the intermediate sleeve 58is rotatably mounted wherein its flange-segment 48, 50, 52, 54 and 56fluid tight-slideably on the inner jacket surface of the intermediatesleeve 58 lies, is in a with respect to the axial thickness of itspiston segment 48 through 56 the axial thickness of the correspondingjacket segment 61 through 69 corresponding segment-constructionally ofits ring disk shaped piston segments 48 through 56 formed, which againare solidly welded to each other.

In the piston 19, for discussion of which reference can in particular bemade to the detailed representation of FIG. 3a as well as thelongitudinal sectional representation of FIGS. 1a and 1 b, is by theconnection side end flange segment 48, which has the same diameter d_(i)as the next adjacent separation flange segment 50 and which forms in theintermediate T-groove segment 49 of the piston 19 a T-ring groove 91′″,which via radial through-going transverse channels 165 of the T-ringgroove segment 62 of the intermediate sleeve 58 is in constantcommunication connection with the T-ring space 91″.

Through the other, on the operating side of the valve 10 provided endflange segment 56 of the piston 19 which has the same diameter d_(i) asthe next adjacent B-separation flange segment 54 and which between thisposition is provided P-groove segment 55 of smaller outer diameter isformed a P-ring groove 94′″, which via radial transverse channels 170 ofthe T-ring groove segment 68 of the intermediate sleeve 58 is inconstant communicating connection with the P-ring space 94″ of the valve10.

Between the A-separation flange segment 50 and the central ring flangesegment 52 of same diameter d_(i) of the piston 19 is provided, withinthe A-ring groove segment 64 of the intermediate sleeve 58, an A-controlsegment 51 of the piston 19, which is provided with a total of fourradial outer open longitudinal grooves 167 ₁ through 167 ₄ extendingbetween the A-separation flange segment 50 and the central ring flange152.

A B-control segment 53 of the piston 14 is provided between theB-separation flange segment 54 and the central ring flange segment 52 ofthe piston 19 within the B-ring notch segment 66 of the intermediatesleeve 58, which again is provided with a total of four radially outeropen longitudinal notches 168 ₁ through 168 ₄ extending themselvesbetween the B-separation flange segment 54 and central ring flangesegment 52 of the piston 19. The longitudinal grooves 167 ₁ through 167₄ of the A-control segment 51 and the longitudinal grooves 168 ₁ through168 ₄ of the B-control segment 53 are provided in groups of four axiallysymmetric with respect to the central longitudinal axis 72′ of thepiston 19, wherein the longitudinal grooves 167 ₁ through 167 ₄ of theA-control segment 51 and the longitudinal grooves 168 ₁ through 168 ₄ ofthe B-control segment 53 of the piston 19 pair-wise are aligned witheach other. These in longitudinal direction pair-wise with each otheraligned longitudinal notches of the A-control segment 51 and theB-control segment 53 are connected by closed right-angled edgedthroughput channels 169 ₁ through 169 ₄ of the central ring flangesegment 52 appropriately communicating pair-wise with each other.

The piston-fixed common longitudinal central plane 173 of the each otherdiametrically oppositely lying longitudinal grooves 167 ₁ and 167 ₃ ofthe A-control segment 51, which each other diametrically oppositelylying arranged throughput channels 169 ₃ and 169 ₃ of the central ringflange 52 as well as the diametrically oppositely lying longitudinalgrooves 168 ₁ and 168 ₃ of the B-control segment 153 is also the commonlongitudinal central plane of the diametrically oppositely lyingP-throughput channels 176 and 177 of the B-separation flange segment 154of the piston 19, via which the respective, with each other aligned,longitudinal grooves of the A-control segment 51 and the B-controlsegment 53 as well as the with this communicating throughput channel 169₁ and 169 ₃ of the central ring flange segments 52 with the P-ring notch94′″ of the piston 19 are in constant communicating connection.

The to the first mentioned piston fixed longitudinal central plane 173right angled running, piston fixed, common longitudinal middle plane 178of the respective other two, each other diametrically oppositely lyinglongitudinal grooves 167 ₂ and 167 ₄ of the A-control segment 51, thediametrically oppositely lying arranged through channel 169 ₂ and 169 ₄of the central ring flange segment 52 as well as the furtherdiametrically oppositely lying longitudinal groove 168 ₂ and 168 ₄ ofthe B-control segment 53 is also a common longitudinal middle plane ofthe diametrically oppositely lying T-throughput channels 171 and 172 ofthe A-separation flange segment 50 of the piston 19, via which therespective with each other aligned longitudinal notches 167 ₂ and 167 ₄as well as 168 ₂ and 168 ₄ of the A-control segment 51 or as the casemay be B-control segment 53 as well as this communicating throughputchannels 169 ₂ and 169 ₄ of the central ring flange segment 52 are inconstant communicating connection with the T-ring notch 91′″ of thepiston 19.

The effective azimuthal width of the longitudinal notches 167 ₁ through167 ₄ of the A-control segment as well as longitudinal groove 168 ₁ and168 ₄ of the B-control segment 53 of the piston 19, which is determinedby the angular separation of the radial outer longitudinal edge 179 and181 of their parallel to each other running groove side edge surfaces182 and 183, corresponds to 90° and is therewith at the same time theazimuthal separation of the radial inner longitudinal edge 164 ₁ and 164₂ as well as 164 ₃ and 164 ₄ of the axial control slit 147 and 148 ofthe A-ring groove segment 64 of the intermediate sleeve 58 (the samerelation applies for the longitudinal grooves 168 ₁ through 168 ₄ of theB-control segment 53 of the piston 19 and the with this coaxial ringgroove segment 66 of the intermediate sleeve 58).

An output present on the P-supply connection 11 of the valve pressure Pof the pressure supply aggregate 29 (FIG. 2) is coupled in via theP-longitudinal channel 97 (FIG. 1a) of the housing 43 also in thisP-ring channel 97″ and from the same via the radial transverse channel170 of the intermediate sleeve 58 in the P-ring groove 94′″ of thepiston 19 as well as in the two P-control channels 184 and 186 (FIG.1b), which extends itself beginning with the P-throughput channels 176and 177 of the B-separation flange segment 54 of the piston 19 up to theA-separation flange segment 50 of the piston 19, which closes off theP-control channel 184 and 186 against the T-ring groove 91′″ if thepiston 19. Further there are T-control channels 187 and 188 (FIG. 1a)which, beginning with the T-throughput channels 171 and 172 of theA-separation flange segment 50, extend up to the B-separation flangesegment 54 of the piston 19 and through these against the P-ring groove94′″ of the piston 19 are blocked off, connected communicating with thetank 32 of the pressure supply aggregate 29.

In the base position 0 of the valve 10 the P-control channels 184 and186 as well as the T-control channels 187 and 188 are blocked offagainst the A-connection groove 92 and the B-connection groove 93 of thehousing 34. This blockage function of the valve 10 in its base position0 is then given, when the control slits 147 and 148 of the A-ring groovesegment 64 as well as the control slits 149 and 151 of the B-ring groovesegments 66 of the intermediate sleeve 58 through respectively two ofthe diametrically oppositely lying in cross-section sector shapedlongitudinal posts 189 ₁ through 189 ₄ and 191 ₁ through 191 ₄ of theA-control segment 51 or as the case may be the B-control segment 53 ofthe piston 19, with their longitudinal grooves 167 ₁ through 167 ₄ or asthe case may be 168 ₁ through 168 ₄ azimuthally block off against eachother, are radially closed.

This is in the embodiment 10 selected for explanation purposes, forwhich a housing-fixed arrangement of the intermediate sleeve 58 waspresumed, then the case, when the piston fixed, respectively commonlongitudinal middle plane 192 and 193 of the pair-wise oppositelyarranged sector shaped longitudinal cross-pieces 189 ₁ through 189 ₄ ofthe A-control segment 151 or as case may be the B-control segment 53 ofthe piston 19 have the same orientation as the housing fixedlongitudinal middle plane 162 and 163 of the control slits 147 and 148of the A-ring groove segment 64 or as the case may be the control slit149 and 151 of the B-ring segment 66 of the intermediate sleeve 58 whichwith the vertical longitudinal middle plane 101 of the housing 34encloses an angle of respectively 45°.

The base position 0 of the valve 10 corresponds to the configuration ofthe ring disk shaped segments 61 through 69 of its intermediate sleeve58 shown exploded along the axis 72 ₁ in the FIGS. 3 and 3a as well asthe circular disk shaped segments 48 through 56 of the valve piston 19.

In this base position the radial outer longitudinal edges 179 and 181 ofthe groove side-wall-longitudinal surfaces 182 and 183, between whichpair-wise also the curved edges of the sector shaped longitudinalcross-member 189 ₁ through 189 ₄ as well as 191 ₁ through 191 ₄ of theA-control segment 51 or as case may be the B-control segment 53 of thepiston 19 extend, with the same registry with the radial innerlongitudinal edges 164 ₁ through 164 ₄ and 166 ₁ through 166 ₄ of thecontrol slits 147 and 148 of the A-ring groove segment 64 of as the casemay be the control slits 149 and 151 of the B-ring groove segment 166provided.

Beginning with the base position 0 of the valve 10, this arrives byturning of the piston 19 in the direction of the arrow 21 of FIG. 3 inthe along the central axis 72 ₂ exploded represented configuration ofits intermediate sleeve segments 61 through 69 as well as the pistonsegments 48 through 56, in which by overlapping the interstitial spacecross-sections of the longitudinal grooves 167 ₁ and 167 ₃ of theA-control segment 51 of the piston 19 which with the interstitial spacecross-sections of the control slits 147 and 148 of the A-ring groovesegment 64 of the A-user connection 13 of the valve 10 is connected withits P-supply connection 11 and through the overlapping of theinterstitial space cross-sections of the longitudinal grooves 168 ₂ and168 ₄ of the B-control segment 53 of the piston 19 with the interstitialspace cross-sections of the control slits 149 and 151 of the B-ringsegments 66 of the B-user connection 14 of the valve 10 is connectedwith its T-return flow connection 12, that is, the valve 10 assumes thefunctional position I.

Alternatively thereto, the valve 10 is brought into, again beginningwith its base position 0, by rotation of its piston 19 in the directionof the arrow 27 in FIG. 3 in the along the central longitudinal axis 72₃ of in FIG. 3 exploded represented configuration of its intermediatesleeve segments 61 through 69 as well as the piston segments 48 through56, in which through the overlapping of the interstitial spacecross-sectional segments of the longitudinal grooves 167 ₂ and 167 ₄ ofthe A-control segments 51 of the piston 19 with the interstitial spacecross-sectional segments of the control slit 147 and 148 of the A-ringgroove segment 64 the A-user connection 13 of the valve 10 is connectedwith its T-return flow connection 12 and through the overlapping of theinterstitial cross-sectional segments of the longitudinal grooves 168 ₂and 168 ₄ of the B-control segments 53 of the piston 19 with theinterstitial space cross-sectional segments of the control slits 149 and151 of the B-ring groove segments 66 of the intermediate sleeve 58 theB-supply connection 14 of the valve 10 is connected with its P-supplyconnection 11, that is, the valve 10 assumes its functional position II.

A hydraulic valve 10′ with functional positions and path connectionsexplained by way of example on the basis of FIGS. 1 through 3 is also,as represented in schematically simplified manner in FIG. 4, realizablein the manner, that the housing 34 of the valve 10 is fixedly connectedwith its piston 19′ and the intermediate sleeve 58′ is providedrotatably relative to the unitary construction formed by the piston 19′and the housing 34′.

As control drive for the housing 58′ there may suitably be employed forexample an electric motor 194 with reversible direction of rotation,which drives a pinion gear 196, which engages with an outer teething 197of an end segment 198 of the intermediate sleeve 58′ extending out fromthe housing 34′.

This type of control is also envisioned in the rotary slide valve 10″represented in FIG. 5, in which both the intermediate sleeve 58″ as wellas also the central piston 19′ are constructed to be rotatable relativeto each other and to the housing 34″. This rotary slide valve 10″ isformed as a follow-up control valve, which is employable for example fordrive control of a rotary-hydraulic motor 199, of which the drive shaft201 is fixed against rotation or via a not shown slit free drive, thatis, a tooth gear drive without play, is rotatingly moveably coupled withthe piston 19″, which is employed as “mechanical” feedback element forthe respective azimuthal position of the drive shaft 201 of thehydraulic motor 199. The desired value input for this position isachieved by the driving of the intermediate sleeve 58″ by means of thepinion 196 driven electric motor 194, which in this case advantageouslyis digitally controllable, that is, is controllable by a series ofelectrical impulses, wherein each of these impulses corresponds to arotation of the pinion 196 about a defined, incremental rotation angleΔφ, which is also associated with an incremental rotation angle δφ ofthe motor shaft 201 of the hydraulic motor 199. The relationship δφ/Δφis hereby determined by the transmission translation, with which therotatorial movement of the drive shaft 202 of the drive control motor194 transmits upon the intermediate sleeve 58″ and the rotation of thedrive shaft 201 of the control hydraulic motor 199 or as the case may beupon the piston 19″ is fed back to the servo-regulator valve 10″.

It is understood, that a follow up control valve constructed as a rotaryslide valve of the type described with reference to FIG. 5 could also berealized in the manner, that the desired position value-input for thedrive-controlled element is produced by electric controlled drive of thevalve piston and the position-actual-value feed-back is produced byrotational coupling of the drive controlled element with theintermediate sleeve of the follow up control valve.

In particular in the embodiment of valves 10 and 10″ discussed on thebasis of FIG. 4 and 5 in which the intermediate sleeve 58′ or as thecase may be 58″ moveably is provided, it is advantageous, that the underhigh initial pressure of the pressure supply aggregate 29 existingP-throughput channel 169 ₁ and 169 ₃ of the central ring flange segment52 of the piston as well the P-throughput channel 176 and 177 of theB-separation flange segment 54 within its segments 53 and 54 is closededged, so that in the area of the central ring flange segment 52 as wellas in the area of the B-separation flange segments 54 a through thepressure caused radial force upon the intermediate sleeve 58′ or as thecase may be 58″ is avoided, which would have the tendency to spreadapart the this ring flange segment 52 and 54 of the piston 19circumscribing ring flange element 56 and 57 of the intermediate sleeveand thus contribute to an overall difficulty of movement of theintermediate sleeve. This reduction of the tendency to spreading apartand therewith to increase rubbing friction upon the housing actingforces is, thanks to the segment construction manner of the piston 19,in simple manner made possible, which therewith also in functionalrespects imparts the advantage of a high functional reliability.

What is claimed is:
 1. A hydraulic valve, comprising: a valve housing composed of planar parallel, plate-shaped segments (36-46), the valve housing (34) having a longitudinal axis (72), longitudinal channels, radial channels, a central valve channel (71), and central channel widening grooves defined therein, wherein: said longitudinal channels (96, 97) are comprised of channel segments formed by through-holes through said plate-shaped segments, said through-holes having a cross-section with a closed edge, said channel segments being in communication with adjoining channel segments of adjacent plate-shaped segments to form said longitudinal channels, said central valve channel (71) is formed by adjoining central openings (75, 77, 79 and 81) of adjacent housing segments (38, 40, 42 and 44), said radial channels are in communication with a supply connection (11, 12) or a user connection (13, 14), and said radial channels or segments of such channels are formed by radial extensions (86-98) of said central openings (75, 77, 79 and 81) of said plate-shaped valve housing segments (38, 40, 42 and 44), and said central channel widening grooves (91, 92, 93 and 93) widen the cross-section of the central channel (71); and a valve piston (19) mounted in said central valve channel (71) for movement in at least one of sliding in the longitudinal direction and rotation in a pressure-tight manner; wherein various functional positions of the valve piston relative to the valve piston housing define various combinations or subcombinations of flow paths, wherein segments of such flow paths are formed by said grooves and channels in at least one of the housing and the piston, which flow path sections are in fluid communication with at least one of (a) each other, (b) pressure-connections, (c) tank-connections, and (d) user connections; and wherein said valve housing plate-shaped segments (36-46) are joined by brazing after at least one of form-fittingly and materially assembling said plates into a dimensionally stable package with brazing material introduced into closed compartments which are formed by groups of interconnected through-holes (121 to 124, 126) of the segment plates (37-45), which compartments extend over the whole series of joints of the segment plates (36 to 46).
 2. A hydraulic valve according to claim 1, wherein said valve housing is composed of planar parallel, plate-shaped segments (36-46) including end plates (36 and 46), and wherein receiver compartments for soldering material are provided, which extend over the entire length of the valve housing between the end plates (36 and 46).
 3. A hydraulic valve according to claim 1, wherein at least one of said closed compartments into which brazing material is introduced forms a continuous channel contacting every valve housing plate shaped segment.
 4. A hydraulic valve according to claim 1, wherein preformed chambers for receiving of brazing material are arranged axially symmetrically with respect to this central longitudinal axis (73) of the central channel (71) of the housing (34).
 5. A hydraulic valve according to claim 1, wherein the plate shaped segments (36 through 46) for the brazing process are held together by fixing posts (116 through 119), which extend between the end segments (36 and 46) of the segment package through aligned fastening through-holes (108).
 6. A hydraulic valve according to claim 5, wherein said valve housing is composed of planar parallel, plate-shaped segments (36-46) including end plates (36 and 46), and wherein post-shaped metal fasteners are provided as fixing elements, which at least on one side of the packet are riveted with the corresponding end face plate (36 or 46).
 7. A hydraulic valve according to claim 5, wherein the fixing posts (116 through 119) are respectively riveted to one end face plate (36 and 46).
 8. A hydraulic valve according to claim 5, wherein the diameter of the fixing posts (116 through 119) corresponds to the diameter of the aligned fastening through-holes (108) of the housing segments (136 through 146).
 9. A hydraulic valve according to claim 1, wherein the plate-shaped segments (36 through 46) of the housing (34) are force form lockingly held together by wedging over with an anchoring body introduced into aligned edge open recesses of the plate shaped segments (36 through 46).
 10. A hydraulic valve according to claim 9, wherein the edge open recesses aligned with each other form a longitudinal notch with an outwardly narrowing, trapezoid shaped interstitial area cross section in which a slightly warped anchoring body is introduceable which by pressing into the notch produces the force form locking anchoring of the plate shaped segments (36 through 46).
 11. A hydraulic valve according to claim 1, wherein the plate shaped segments (36 through 46) of the housing (34) are materially lockingly connected with each other by a least one outer weld bead.
 12. A hydraulic valve according to claim 1, wherein at least some of the plate shaped segments (36 through 46), which are provided adjacent to each other, are provided with coaxially aligned projections and recesses of approximately complimentary shape and wherein said plate shaped segments are engaged by pressing in of the projections of one segment plate into the recesses of an adjacent segment plate.
 13. A hydraulic valve according to claim 12, wherein the projections on one side of said plate shaped segments are formed by the material from stamped out recesses of the opposite side of said plate shaped segments, in which the stamping stroke which formed the recesses extends only through a part of the material thickness of the respective segment plate.
 14. A hydraulic valve according to claim 1, wherein the valve piston (14) is comprised of circular disk shaped segment plates (48 through 56) solidly welded with each other.
 15. A hydraulic valve according to claim 1, wherein an intermediate sleeve (58) is provided introduced in the central channel (71) of the housing (34), which co-axially encompasses the piston (19) and for its part is comprised of ring shaped, solidly with each other welded segments (61 through 69) of the same inner diameter d_(i).
 16. A hydraulic valve according to claim 15, wherein the intermediate sleeve (58) is connected fixedly with the housing (34) of the valve and the piston (19) is provided moveably in the intermediate sleeve (58).
 17. A hydraulic valve according to claim 15, wherein the intermediate sleeve (58) is fixedly connected with the piston (19) of the valve (10) and wherein the unitary element formed by the intermediate sleeve (58) and the piston (19) collectively is moveable relative to the housing (34) of the valve (10).
 18. A hydraulic valve according to claim 15, wherein the piston (19) of the valve (10) is fixedly connected with the housing (34), and the intermediate sleeve (58) is provided moveable relative to said housing.
 19. A hydraulic valve according to claim 15, wherein both the piston (19) as well as the intermediate sleeve (58) are moveable relative to the housing (34) as well as with respect to each other.
 20. A hydraulic valve according to claim 1, wherein two of said closed compartments into which brazing material is introduced together contacting every valve housing plate shaped segment and with respect to each other are interrupted by only one segment.
 21. A hydraulic valve according to claim 1, wherein the thickness of the plate shape segments (38, 40, 42, 44) of the housing (34), of which the central opening defining edges (75, 77, 79, 81) form the base groove of central channel (71) widening grooves (91, 92, 93, 94), correspond to the axial separation between the groove side-wall forming segment plates (37, 39, 41, 43, 45) or a normal breech of this separation.
 22. A hydraulic valve according to claim 21, wherein the plate shaped segments (36 through 46) of the valve housing (34) have the same thickness.
 23. A hydraulic valve according to claim 1, wherein the thickness of plate segments (39, 41, 43) corresponds to one of (a) the side walls of a ring flange separating two housing ring grooves (91, 92, 93, 94) from each other, and (b) a natural breech of the same.
 24. A hydraulic valve as in claim 1, wherein said valve piston includes piston grooves.
 25. A hydraulic valve as in claim 1, wherein said valve piston includes piston channels. 